I-131 rose bengal has been a valuable diagnostic agent for hepatobiliary tests but its use has declined recently from concern over absorbed radiation dose from the I-131 as well as inefficient detection of the 364-keV I-131 photon with a gamma camera. Rose bengal labeled with I-123 does not have these drawbacks and has been evaluated in a limited clinical study which concluded that the larger photon flux from larger permissible amounts of the I-123 agent would prove advantageous in the differentiation between hepatocellular and extrahepatic obstructive jaundice. This study was reported in the Journal of Nuclear Medicine, July, 1975, Vol. 16, No. 7, pages 629-632, and was authored by A. N. Serafini et al.
The 13 hour half life of I-123 presents a problem to users unless the period from the end of production to clinical administration is sufficiently short. This problem can be minimized by the utilization of cold kits and the present invention provides such a cold kit.
The present methods of preparing radioiodinated rose bengal require temperatures from between 50.degree.-120.degree. C. and reaction times of 1 hour or more. Representative methods are revealed by P. Rabin et. al., "A New Method of Labelling Rose Bengal With I-131 or I-125," International Journal of Applied Radiation Isotopes, 19, pp. 361-367, 1968 and A. A. Sunar et. al., "Preparation of Iodine-131 Labeled Rose Bengal," Radiochemical Acta, 12, 119, 1969.